The invention is directed to a medical device and method to apply repetitive compression forces to the body of a person to aid blood circulation, loosening and elimination of mucus from the lungs of a person and relieve muscular and nerve tensions.
Clearance of mucus from the respiratory tract in healthy individuals is accomplished primarily by the body""s normal mucociliary action and cough. Under normal conditions these mechanisms are very efficient. Impairment of the normal mucociliary transport system or hypersecretion of respiratory mucus results in an accumulation of mucus and debris in the lungs and can cause severe medical complications such as hypoxemia, hypercapnia, chronic bronchitis and pneumonia. These complications can result in a diminished quality of life or even become a cause of death. Abnormal respiratory mucus clearance is a manifestation of many medical conditions such as pertussis, cystic fibrosis, atelectasis, bronchiectasis, cavitating lung disease, vitamin A deficiency, chronic obstructive pulmonary disease, asthma, and immotile cilia syndrome. Exposure to cigarette smoke, air pollutants and viral infections also adversely affect mucociliary function. Post surgical patients, paralyzed persons, and newborns with respiratory distress syndrome also exhibit reduced mucociliary transport.
Chest physiotherapy has had a long history of clinical efficacy and is typically a part of standard medical regimens to enhance respiratory mucus transport. Chest physiotherapy can include mechanical manipulation of the chest, postural drainage with vibration, directed cough, active cycle of breathing and autogenic drainage. External manipulation of the chest and respiratory behavioral training are accepted practices as defined by the American Association for Respiratory Care Guidelines, 1991. The various methods of chest physiotherapy to enhance mucus clearance are frequently combined for optimal efficacy and are prescriptively individualized for each patient by the attending physician.
Cystic fibrosis (CF) is the most common inherited life-threatening genetic disease among Caucasians. The genetic defect disrupts chloride transfer in and out of cells, causing the normal mucus from the exocrine glands to become very thick and sticky, eventually blocking ducts of the glands in the pancreas, lungs and liver. Disruption of the pancreatic glands prevents secretion of important digestive enzymes and causes intestinal problems that can lead to malnutrition. In addition, the thick mucus accumulates in the lung""s respiratory tracts, causing chronic infections, scarring, and decreased vital capacity. Normal coughing is not sufficient to dislodge these mucus deposits. CF usually appears during the first 10 years of life, often in infancy. Until recently, children with CF were not expected to live into their teens. However, with advances in digestive enzyme supplementation, anti-inflammatory therapy, chest physical therapy, and antibiotics, the median life expectancy has increase to 30 years with some patients living into their 50""s and beyond. CF is inherited through a recessive gene, meaning that if both parents carry the gene, there is a 25 percent chance that an offspring will have the disease, a 50 percent chance they will be a carrier and a 25 percent chance they will be genetically unaffected. Some individuals who inherit mutated genes from both parents do not develop the disease. The normal progression of CF includes gastrointestinal problems, failure to thrive, repeated and multiple lung infections, and death due to respiratory insufficiency. While some patients experience grave gastrointestinal symptoms, the majority of CF patients (90 percent) ultimately succumb to respiratory problems.
A demanding daily regimen is required to maintain the CF patient""s health, even when the patient is not experiencing acute problems. A CF patient""s CF daily treatments may include:
Respiratory therapy to loosen and mobilize mucus;
Inhalation therapy with anti-inflammatory drugs, bronchodilators and antibiotics for infections;
Oral and intravenous antibiotics to control infection;
Doses of Pulmozyme to thin respiratory mucus;
20 to 30 pancreatic enzyme pills taken with every meal to aid digestion;
a low-fat, high-protein diet;
Vitamins and nutritional supplements; and
Exercise.
A lung transplant may be the only hope for patients with end stage cystic fibrosis.
Virtually all patients with CF require respiratory therapy as a daily part of their care regimen. The buildup of thick, sticky mucus in the lungs clogs airways and traps bacteria, providing an ideal environment for respiratory infections and chronic inflammation. This inflammation causes permanent scarring of the lung tissue, reducing the capacity of the lungs to absorb oxygen and, ultimately, sustain life. Respiratory therapy must be performed, even when the patient is feeling well, to prevent infections and maintain vital capacity. Traditionally, care providers perform Chest Physical Therapy (CPT) one to four times per day. CPT consists of a patient lying in one of twelve positions while a caregiver xe2x80x9cclapsxe2x80x9d or pounds on the chest and back over each lobe of the lung. To treat all areas of the lung in all twelve positions requires pounding for half to three-quarters of an hour along with inhalation therapy. CPT clears the mucus by shaking loose airway secretions through chest percussions and draining the loosened mucus toward the mouth. Active coughing is required to ultimately remove the loosened mucus. CPT requires the assistance of a caregiver, often a family member but a nurse or respiratory therapist if one is not available. It is a physically exhausting process for both the CF patient and the caregiver. Patient and caregiver non-compliance with prescribed protocols is a well-recognized problem that renders this method ineffective. CPT effectiveness is also highly technique sensitive and degrades as the giver becomes tired. The requirement that a second person be available to perform the therapy severely limits the independence of the CF patient.
Artificial respiration devices for applying and relieving pressure on the chest of a person have been used to assist in lung breathing functions, and loosening and eliminating mucus from the lungs of CF persons. Subjecting the person""s chest and lungs to pressure pulses or vibrations decreases the viscosity of lung and air passage mucus, thereby enhancing fluid mobility and removal from the lungs. These devices use vests having air-accommodating bladders that surround the chests of persons. Mechanical mechanisms, such as solenoid or motor-operated air valves, bellows and pistons are disclosed in the prior art to supply air under pressure to diaphragms and bladders in regular pattern or pulses. The bladder worn around the thorax of the CF person repeatedly compresses and releases the thorax at frequencies as high as 25 cycles per second. Each compression produces a rush of air through the lobes of the lungs that shears the secretions from the sides of the airways and propels them toward the mouth where they can be removed by normal coughing. External chest manipulation with high frequency chest wall oscillation was reported in 1966. Beck G J. Chronic Bronchial Asthma and Emphysema. Rehabilitation and Use of Thoracic Vibrocompression, Geriatrics (1966), 21: 139-158.
G. A. Williams in U.S. Pat. No. 1,898,652 discloses an air pulsator for stimulating blood circulation and treatment of tissues and muscles beneath the skin. A reciprocating piston is used to generate air pressure pulses which are transferred through a hose to an applicator having a flexible diaphragm. The pulsating air generated by the moving piston imparts relatively rapid movement to the diaphragm which subjects the person""s body to pulsing forces.
J. D. Ackerman et al in U.S. Pat. No. 2,588,192 disclose an artificial respiration apparatus having a chest vest supplied with air under pressure with an air pump. Solenoid-operated valves control the flow of air into and out of the vest in a controlled manner to pulsate the vest, thereby subjecting the person""s chest to repeated pressure pulses.
J. H. Emerson in U.S. Pat. No. 2,918,917 discloses an apparatus for exercising and massaging the airway and associated organs and loosening and removing mucus therefrom. A blower driven with a motor creates air pressure for a device that fits over a person""s nose and mouth. A diaphragm reciprocated with an electric motor pulses the air flowing to the device and the person""s airway. The speed of the motor is controlled to regulate the number of vibrations per minute.
R. F. Gray in U.S. Pat. No. 3,078,842 discloses a bladder for cyclically applying an external pressure to the chest of a person. A pressure alternator applies air pressure to the bladder. A pulse generator applies air pressure to the bladder to apply pressure pulses to the chest of the person.
R. S. Dillion in U.S. Pat. No. 4,590,925 uses an inflatable enclosure to cover a portion of a person""s extremity, such as an arm or leg. The enclosure is connected to a fluid control and pulse monitor operable to selectively apply and remove pressure on the person""s extremity.
W. J. Warwick and L. G. Hansen in U.S. Pat. Nos. 4,838,263 and 5,056,505 disclose a chest compression apparatus having a chest vest surrounding a person""s chest. A motor-driven rotary valve allows air to flow into the vest and vent air therefrom to apply pressurized pulses to the person""s chest. An alternative pulse pumping system has a pair of bellows connected to a crankshaft with rods operated with a dc electric motor. The speed of the motor is regulated with a controller to control the frequency of the pressure pulses applied to the vest. The patient controls the pressure of the air in the vest by opening and closing the end of an air vent tube.
C. N. Hansen in U.S. Pat. Nos. 5,453,081 and 5,569,170 discloses an air pulsating apparatus for supplying pulses of air to an enclosed receiver, such as a vest located around a person""s chest. The apparatus has a casing with an internal chamber containing a diaphragm. An electric operated device, such as a solenoid, connected to the diaphragm is operated with a pulse generator to vibrate the diaphragm to pulse the air in the chamber. A hose connects the chamber with the vest to transfer air and air pulses to the vest which applies pressure pulses to the person""s chest.
N. P. Van Brunt and D. J. Gagne in U.S. Pat. Nos. 5,769,797 and 6,036,662 disclose an oscillatory chest compression device having a wall with an air chamber and a diaphragm mounted on the wall and exposed to the air chamber. A rod pivotally connected to the diaphragm and rotatably connected to a crankshaft transmits force to the diaphragm during rotation of the crankshaft. An electric motor drives the crankshaft at selected controlled speeds to regulate the frequency of the air pulses generated by the moving diaphragm. An air flow generator, shown as a blower, delivers air to the air chamber to maintain the pressure of the air in the chamber. Controls for the motors that move the diaphragm and blower are responsive to the pressure of the air in the air chamber. These controls have air pressure responsive feedback systems that regulate the operating speeds of the motors to control the pulse frequency and air pressure in the vest.
The invention comprises a vest used to apply repetitive pressure pulses to a human body and a pulsator for generating air pressure pulses that are transmitted to the vest to provide secretion and mucus clearance therapy. The vest has a non-elastic outer cover attached to a flexible liner. An air core of flexible material located between the cover and liner is connected with a hose to an air pulsator operable to generate repetitive air pressure pulses which are transmitted to the air core. The air pressure pulses subjected to the air core create repetitive pressure pulses that are transmitted to the body of a person wearing the vest whereby high frequency chest wall oscillations or pulses enhance mucus clearance in the respiratory system of the person. The pulsator has a casing with an internal air pulsing chamber in air communication with the hose which transmits air and air pressure pulses to the air core. The air pressure pulses are generated with a movable diaphragm mounted on the casing having one side in communication with the air pulsing chamber. A motion transmitting mechanism driven with a variable speed power unit linearly reciprocates the diaphragm to repetitively increase and decrease the pressure of the air in the internal chamber thereby generating air pressure pulses. The operating speed of the power unit is regulated to change the air pressure pulse frequency. The case has an air pumping chamber in communication with the other side of the diaphragm. The reciprocating diaphragm pumps air under pressure into the air pulsating chamber. A one-way valve mounted on the casing allows air under pressure to flow from the air pumping chamber into the air pulsating chamber and prevent the reverse flow of air from the air pulsating chamber back to the air pumping chamber thereby maintaining the air in the air pulsating chamber at a desired pressure. An adjustable air flow restrictor limits the flow of air into the air pumping chamber thereby controlling the pressure of the air in the air pumping chamber, air pulsating chamber, and air core located in the vest.
The preferred embodiment of the body pulsating apparatus has a case with walls surrounding an air pulsing chamber. An elongated hose carries air and air pulses to an air core in a vest located about the upper body of a person. The case has an internal wall that separates the air pulsing chamber from an air manifold chamber. One or more one-way valves mounted on the internal wall allow air to flow from the air manifold chamber into the air pulsing chamber and prevent reverse flow of air back from the air pulsing chamber into the air manifold chamber. The case has top and bottom openings covered with diaphragms attached with flexible peripheral members to the case to enclose the air pulsing chamber. Located within the air pulsing chamber is a pair of linear reciprocating motion transmitting mechanisms for linearly moving the diaphragms in straight line opposite directions to pulse the air in the air pulsing chamber. The motion transmitting mechanisms are scotch yoke devices which provide the diaphragms with straight line harmonic motions. An electric motor rotates a common shaft having a pair of eccentrics that laterally moves shuttles and reciprocates yokes. The yokes are fixed directly to the diaphragms. The operating speed of the motor is controlled with a motor controller wired to a timer and a source of electric power. The controller is manually adjustable to change the speed of the motor which is proportional to air pulse frequency in the air pulsing chamber. Covers located over the diaphragms attached to the casing have air pumping chambers in communication with the manifold chamber. The reciprocating movements of the diaphragms draws air through an air flow control into air manifold chamber and pumping chambers and compresses the air in the air manifold chamber. The pressure of the air in the air manifold chamber is regulated with a manually adjustable air flow control valve. Restricting the flow of air into the manifold chamber reduces the pressure of the air in the air manifold chamber. When the pressure of the air in the air manifold chamber exceeds the air pressure in the air pulsing chamber, the one-way valve opens to allow air to flow into the air pulsing chamber, through the hose, and into the air core thereby inflating the air core which applies pressure to the upper body of a person wearing the vest. The reciprocating movements of the diaphragms pulse the pressurized air at a frequency determined by the speed of the electric motor that drives the scotch yokes.